Walmart offers five quarts of Havoline Motor Oil in four varieties starting at $6.77 after this mail-in rebate. (Amazon offers many of these items for the same price for Prime members.) Opt for in-store pickup (where available) to avoid the $4.97 shipping fee. That's a savings of up to $8 compared to what you'd pay at other stores. You can choose from 1-quart and 5-quart options, but the total must be at least five quarts. Rebate expires April 30.